The quality of end user experience in the Wireless Networks is important for the network operators because it is one of the elements that attracts and keeps subscribers and builds customer loyalty. For that reason, wireless network operators track network performance indicators and demand from telecommunications equipment vendors that certain performance criteria are met to satisfy a level of quality of the end user experience. Various metrics to measure the performance of the network are generally referred to as Key Performance Indicators (KPI). One of these performance indicators is network latency.
There are currently many methods and ubiquitous tools to measure the end-to-end latency in commercial communications networks, which are suitable either to confirm good results or to point out an issue in the network, but it is more difficult to track the contribution of each network element and end user equipment on the network latency in order to determine the source of latency problems. Typically, external network analyzers or test equipment are required to be inserted at each of the external interfaces in the network in order to determine the source of latency problems, which is not cost effective for live networks. FIG. 1 illustrates a simplified UMTS (Universal Mobile Telecommunications System) network 100, having network elements RNC (Radio Network Controller) 102, SGSN (Serving GPRS Support Node) 104, NodeB (base station transceiver 106, UE (User Equipment) 108, all supervised by a Network Monitoring system 110. Physical connections are represented by solid lines between network elements, and application layer connections are represented by dashed lines between network elements. Network protocol Analyzers 112A, 112B, 112C are installed at the interfaces between these nodes in order to capture message packets and log the time at which they are captured. In real telecommunications networks with hundreds of nodes and thousands of users, this becomes very impractical. Additionally, network analyzers intercept packets and if these packets are encrypted then decoding is not possible unless an encryption key is provided to the network analyzer which is typically not desirable for security reasons.
In view of the foregoing, it would be desirable to provide a method of measuring signaling plane delay Key Performance Indicators in network elements of a live network while minimizing impact on system performance.